As a larger portion of the human population enters their elderly years there is an increased importance to understand the genetic and environmental factors influencing longevity. Recently, many longevity mutants have been identified and a surprisingly large numbers of these extended longevity mutants also have increased levels of stress resistance. Thus, it may be possible to use increased stress resistance phenotypes that has been shown to be associated with longevity in flies and nematodes, and also is evolutionary interest as adaptation to thermal stress as a common ecological challenge for many species. The present study will use Drosophila melanogaster as a model system to dissect the genetic control of temperature stress resistance phenotypes. The genetic control of temperature stress resistance will be determined by quantitative genetic analysis and QTL mapping, single P element insert mutagenesis of genetically identical lines, as well as surveys of the natural segregating variation in temperature stress resistance. This study will be done in collaboration with a study directly examining the genetics of longevity to determine if the temperature stress resistance loci are the same loci. The discovery of loci associated with stress resistance and longevity in flies will advance studies of longevity in humans as the numerous genome projects have shown there to be great conservation of genes affecting basic biological processes.